Potential toxicity, antibacterial effect and antagonistic activity against Vibrio of a strain of bacterium Pseudoalteromonas piscicida 2515 exposed to heat treatment detoxification
ZHANG Yuzhe1,2, WANG Xiuhua1,3*, YU Danghui1, WANG Fenglin1 , SUN Xiangshan4, HUANG Jingxian4
1.Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs；Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences，Qingdao 266071, China; 2.College of Fisheries and Life Science, Shanghai Ocean University, Shanghai 201306, China; 3.Laboratory for Marine Fisheries Science and Food Production Processes, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China; 4.Xiaying Proliferation Station, Chinese Academy of Fishery Sciences, Weifang 261312, China
Abstract: In order to evaluate the toxicity of a strain of bacterium Pseudoalteromonaspiscicida 2515 (strain 2515) with antagonistic activity against Vibrio spp. to marine animals, and find out an effective heat treatment detoxification method, hemolytic activity on blood cell of sheep, fish and shrimp was tested on blood agar plate and by microscopic observation. Fertilized eggs and larvae of Chinese shrimp Fenneropenaeuschinensis were incubated and reared in a 25 cm in diameter ×40 cm in height plastic bag containing 2 L water with immersion challenge of strain 2515 at a dose of 105, 106, 107 and 108 CFU/mL to investigate the effect of bacterial toxicity on fertilized eggs and larval development of Chinese shrimp. Fluid of strain 2515 fermented for 24 h was diluted into 105 CFU/mL and exposed to 40, 45, 50, 55, 60 and 65 ℃ for 1 h to test inactivation of the strain 2515. The results showed that the strain 2515 had hemolytic activity on red blood cells of sheep and fish, but no hemolytic activity on blood cells of shrimp. There was significantly low survival rate of larvae metamorphosis from nauplius Ⅲ to Zoea Ⅰ exposed to strain 2515 at concentration of higher than 105 CFU/mL (P<0.05). Strain 2515 and its broken liquid treated at 55 ℃ for 1 h led to inactivate the bacterium and hemolytic activity on fish red blood cells, and to increase in antibacterial activity by 55.8%. The findings suggest that strain 2515 has potentially toxic to fish and shrimp larvae. However, strain 2515 treated by appropriate temperature not only remove the strain toxicity but also improve its antibacterial activity, which provides technical support for the development and application of this strain.
2021, Vol. 36 
